# geffect.m

Effective g-tensor for the user-specified Kramers doublet, computed as described in http://dx.doi.org/10.1063/1.4793736

## Syntax

    g=geffect(spin_system,states)


## Description

Lanthanide systems often have multiple pairs of energy levels that are related to one another by a spin flip. These are called Kramers doublets. This function returns the effective g-tensor for the user-specified pair of levels.

## Arguments

   states - the numbers of the states to use
(numbered sequentially from the
lowest to the highest energy)


## Returns

   g      - 3x3 g-tensor matrix in Bohr mag-
neton units


## Examples

See dy_lft_single.m file in examples/giant_spin folder of Spinach distribution.

## Notes

Make sure that the pair of levels specified actually is a Kramers doublet.